ASME IX QW-288.3(e) Interpretation

[The Azar]

Hello Everyone,

I would like to ask if anyone has information about ASME Sec. IX regarding PQR essential variables as per QW-288.3(e)for Tube to Tubesheet heat exchanger weld:
QW-288.3 Gas Tungsten Arc, Plasma Arc, and Gas Metal Arc Welding:
(e) For GTAW or PAW, a change in the nominal diameter of the filler metal or electrode.

Well it is clear enough that the diameter of the filler metal is an essential variable; however, I just need to confirm if this essential variable is a must to be applied in production weld exactly as per PQR layer arrangement, e.g. if PQR root pass filler metal dia was 1.2mm, hotpass dia used 1.6 mm, third layer 2.0 mm, can I use in production weld 1.6 mm dia for root layer and 2.0 mm for balance instead? knowing that PQR already used these sizes with different layers.

Thank you in advance.

AZAR

 

[fleischfresser]

Please take in mind QW-202.6 for the qualification acc. to QW-193.1 (demonstration mockup)
“If specific qualification test requirements are not specified by the applicable Code Section, tube‐to‐tubesheet welds shall be qualified with one of the following methods:
(a) groove welds per the requirements of QW-202.2 and QW-202.4
(b) a demonstration mockup per the requirements of QW-193.1
(c) fillet welds per the requirements of QW-202.2(c) (for nonpressure retaining tube‐to‐tubesheet welds only)”

e.g. ASME Section I and VIII/1 do specific require the use of QW-193.1 but Section VIII/2: Paragraph 6.3.4 require a qualification by a demonstration mockup per the requirements of QW-193.1.

However if QW-193.1 is used for the qualification all variables of QW-288 have to considered. That means you must use on the mockup the same nominal diameter(s) as for the actual production welding.


Regards - Juergen

 

[The Azar]

Juergen,

Thank you for the information, I also believe that the filler metal diameter per layer shall be followed in the actual production weld considering the sensitivity of the joint in order to assure the minimum leak-path length.

Regards,

AZAR

 

[SectionIX]

A good point, but if you so write this into your WPS, you are then bound by this restriction.